This invention relates to wood working machines and more particularly to a device for making patches, especially of wood, and for patching resin galls on pieces of wood.
Devices of this kind are known. For example, disclosed in Swiss patent No. 524 440 is a device for producing resin gall patches from a piece of wood. For serial production of patches of this kind using this device, the end of a strip of end-grained wood is led past a groove milling tool which is composed of several milling disks so that the form of the patches can be milled into the end of the strip. The strip is led linearly while the groove milling tool is led along a modelling roller about the end of the strip, the patches being provided with the corresponding radius. The strip of end-grained wood is then led past a cutting off means, by means of which the profile-cut patches can be separated from the strip. Afterwards the production step starts over again, the strip of wood being brought into the starting position and being advanced by an appropriate amount.
Another device for production of patches is disclosed in U.S. Pat. No. 1,973,757. With this device the pieces of wood to be made into patches are given automatically to a clamping device which, by revolving about a rotational axis, leads them past a milling tool. The corresponding contour is thereby milled into the piece of wood. The clamping device releases the shaped piece, to take up a new piece of wood to be shaped. Here, too, serial production of patches is achieved using a stationary device.
The patching of pieces of wood with corresponding patches takes place almost exclusively at the location of the piece of wood to be patched, that is, for example, at places of production, assembly points or building sites. The craftsman is equipped with a hand milling machine for this purpose with which the milling of the piece of wood to be patched is carried out and in which the suitable patch is glued and can be planed afterwards.
Since, as mentioned above, the patches are serially produced at the location of the stationary production device, and since the aforementioned craftsman handles pieces of wood of differing kinds of wood, he carries a whole assortment of prefabricated patches around with him made of differing kinds of wood. He is thereby able to insert into each piece of wood a patch made from the same type of wood.
As is well known, however, pieces of wood of the same type, especially if they come from different trees, can have differences which are conspicuous and which derive, for example, from differences in color and/or differently running grains.
It is desirable that patches inserted in this way are not visible in the corresponding pieces of wood. This invisibility has not been optimally achieved until now, however, because of to the aforementioned differences between the patches and the pieces of wood to be patched, even when they are of the same type of wood. It would be advantageous if the patch could be made from a remnant of the piece of wood to be patched, which is practically infeasible using the known devices.